The present invention relates to an axle support for a motor vehicle as well as a method for producing the axle support.
Axle supports in motor vehicles generally have two longitudinal supports. The longitudinal supports extend substantially in the longitudinal direction of the vehicle. The two longitudinal supports are connected to one another by transverse supports. The axle support is fastened to the vehicle body. The various connecting members for suspension of the wheels are in turn fastened to the axle support. Axle supports in a motor vehicle are usually made of metal, for example aluminum.
The object of the present invention is to provide an axle support which, with cost-effective production and installation, is as lightweight as possible and ensures a low-maintenance and reliable operation of a motor vehicle. In particular the axle support should be suitable for mass production. Furthermore it is an object of the present invention to provide a corresponding method for producing the axle support.
The object is achieved by an axle support for a motor vehicle, comprising at least one first support and at least one second support fitted onto the first support. A cavity is formed between an outer surface of the first support and an inner face of the second support. This cavity is filled with adhesive. The cavity filled with adhesive secures the connection between the first support and the second support.
Thus according to the invention the two supports of the axle support are connected to one another by a method of injection adhesion. In the axle support the two longitudinal supports (first supports) are particularly preferably made of metal, in particular aluminum casting. In order to achieve a significant saving of weight, the two transverse supports (second support) which connect the two longitudinal supports to one another are made of fiber-reinforced plastic, preferably carbon fiber reinforced plastic (CFRP), for example as braided profiles. Through the construction of the cavity according to the invention which is formed with adhesive it is ensured that the two substrates do not touch. In this way corrosion at the contact point between the fiber-reinforced plastic and the metal is avoided. A coating of the longitudinal support, for example with thick layer cataphoretic paint, is provided as additional protection against corrosion.
Two sealing rings are preferably provided. The two sealing rings close the cavity, so that in injection adhesion no adhesive escapes. At the same time a defined spacing or a defined gap width can be ensured in the cavity by the two sealing rings. In particular the two sealing rings are of U-shaped construction and thus can be fitted onto the front ends of the respective supports.
A channel is preferably constructed in one of the supports. In the interior of the support this channel leads to the cavity. Adhesive can be injected into the cavity via the channel. Particularly preferably the channel is formed in one of the first supports, that is to say preferably in a support made of metal. This has the advantage that a thread can be formed at the inlet into the channel. An inlet hose for the adhesive can be screwed into this thread. Thus the thread constitutes a pressure-resistant connection between the inlet hose and the channel.
The second support made of fiber-reinforced plastic is preferably fitted onto the first support. Since the channel is preferably formed in the metal of the first support, the channel extends in the longitudinal direction of the support beyond the cavity and thus is readily accessible in the production process.
The invention further comprises a method for producing an axle support for a motor vehicle. The embodiments presented in the context of the axle support according to the invention apply correspondingly advantageously to the method according to the invention. The method comprises at least the following steps: (i) providing a first support and a second support, (ii) insertion of the two supports into one another, wherein a cavity is formed between an outer surface of the first support and an inner face of the second support, and (iii) filling of the cavity with adhesive.
Sealing rings are preferably fitted onto the ends of the two supports. As already described above, this has the advantage that the different materials of the support do not touch and at the same time a defined gap is predetermined in the cavity. During the production process a further advantage is obtained due to the sealing ring: When the sealing rings are used the two supports are fixed solely by the fitting together, so that the handling is simplified in the production process.
Bearing blocks to accommodate a gearbox can preferably be disposed in or on the second supports which are constructed as transverse supports. Depending upon the design and construction one of the bearing blocks can be disposed in the overlap region of the two adhered supports. In order to take this into consideration, a recess is preferably constructed in the first support and in the second support. A receptacle for a gearbox mounting can be inserted into this recess at a later stage. During the adhesion process a place-holder element, made for example of plastic, is inserted into the recess. This place-holder element ensures that no adhesive escapes at the edges of the recess during the initiation of the adhesive. After the initiation of the adhesive the place-holder element is removed again and a corresponding receptacle for the transmission or a bearing block can be pressed in.
The injection of the adhesive into the cavity preferably takes place with a vacuum and/or overpressure. In addition to connection of the two supports by the adhesive, it is possible to secure it for example by riveting, screws or the like. This additional securing can also be used only for fixing the position of both supports during the curing of the adhesive.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.